Electric arc welding technology utilizes a power source that passes electrical current between an electrode and a work piece. Typically, the electrode includes welding wire drawn from a drum or reel of welding wire and passed through a contact tip for depositing the welding wire onto the work piece. The power source of the welder typically includes a first stud connected to the electrode and a second stud connected to the work piece. Connections are made via welding cables, which may be quite long possessing a variety of impedance variables, such as inductive reactance based upon length, position and shape of the cables. During the welding process, the power supply receives a command signal to create a particular output signal between the electrode and work piece, which may be a pulse wave. One of the more common power sources is the Power Wave sold by The Lincoln Electric Company of Cleveland, Ohio. The welder must accurately control the output signal, e.g. a constant voltage output or a pulse shape waveform, by controlling the voltage, which may vary during the welding procedure. To ensure the desired welding operation between the electrode and work piece, the output signal or command signal is created based upon feedback from the actual welding operation. This feedback involves the arc current and/or the arc voltage. However, the arc voltage between the electrode and work piece can not be determined by the voltage between the output studs of the power source. Voltage is affected by not only the impedance of the cables, but also the choke and other impedance creating components in the welding operation. To ensure an accurate feedback of the voltage, voltage sensing leads are interconnected between the controller of the power source to the electrode and the work piece. The voltage from the voltage sensing leads determines the command signal to the power source from the controller. Accordingly, negative results affecting the quality of the weld can occur if the voltage sense leads become disconnected from the welding circuit. Since the voltage command to the power source is determined by the voltage feedback signal, a misconnected or disconnected sense lead will provide a feedback signal indicating a faulty change in the arc voltage.
Typically installation of the sense leads requires the operator to open his equipment and configure the power source for the type and polarity of sense leads that he will be using. Dip switches tell the power source what sense leads are connected and with what polarity. If the sense leads are incorrectly configured or installed, weld quality will suffer and in many situations the work piece may be rendered unusable. Material costs, production downtime and set up of the new components can accumulate to considerable losses. In certain instances, the sense leads may also break or otherwise become disconnected from the electrode or work piece. Burn back will likely result causing loss of the welding tip and potential rework of the work piece. It would therefore be advantageous to reduce set up time and lost production costs by using a power source that automatically detects the sense lead configuration and automatically adjusts the feedback accordingly.